M0JRQ

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ANTENNAS
A collection of aerials for HF and VHF

 

The idea is to include design, construction and performance discussion on antennas. It's always interesting to see how things have developed over the years - and how some things haven't! I've been collecting PW, Radio Constructor and other magazines from the fifties and sixties and there are some interesting antenna items there. See some of them here.

Antenna projects
Collins Balun
A 4:1 balun 		Collins balun project: Chris Pearson, M0JRQ, July 2007

 

 

  

2m J-Pole

I made this J Pole as a portable antenna for 2m. Back in 1978, Fred Judd, G2BCX described the design and construction of a derivative of the original J Pole in Practical Wireless magazine. This one was, I'm fairly certain, the original Slim Jim antenna. The aerial has emerged many times, including the Roo Stick by Ian Keyser, G3ROO (RadCom, September 1996) which was probably the inspiration for my aerial.

The antenna has travelled many tens of thousands of miles in the back of my car over the past two years, seeing service in many locations. In the summer of 2007 it was given a fairly rigorous field test by Dave, G0SDO who was - at that time - looking for a suitable design for a VHF portable antenna. It seems to have passed the test, anyway!

 

 

 

 



The design notes, construction details and discussion are here.

2m J-Pole
Antenna in action:
in the snow on Garrowby Hill, New Year's Day
2m J-Pole - Detail
2m J-Pole in sectionsMade in two parts, the aerial can be slotted together quickly
2m J-Pole - Detail of the feedpoint and choke balun
2m J-Pole assembled
  
 

4m mobile whip

I made this whip from the whippy top section of a fibreglass fishing pole covered with the braid froma length of RG58

 

 

 

 


 


It works well! See how it was made here
4m whip antenna
4m whip antenna dwarfes an IC-E90 handheld
Top of the 4m whip antenna
Base of 4m whip antenna and BNC connector
 
4:1 balun for HF
Typical 4:1 balun on a ferrite
Another view of a typical torroidal 4:1 balun
 
The elbow in my 35m end fed antenna at home The corner of my 35m end fed - over the end of the garage